Abaixo está uma instrução que descreve uma tarefa de geração de SQL, combinada com uma entrada que fornece mais contexto sobre os esquemas de tabela disponíveis. Escreva o código SQL que responda adequadamente à solicitação
 ###Instrução: Qual é o objetivo contra listado quando os gols marcados são 30?
 ###Tabelas: CREATE TABLE scoring_leaders (scoring_leaders_id AUTO_INCREMENT PRIMARY KEY, Player VARCHAR, Touchdowns (5 points) INT, Extra points 1 point INT, Field goals (5 points) INT, Total Points INT) CREATE TABLE 2010s (2010s_id AUTO_INCREMENT PRIMARY KEY, Year INT, Network VARCHAR, Play-by-play VARCHAR, Color commentator VARCHAR, Sideline reporters VARCHAR, Pregame host VARCHAR, Pregame analysts VARCHAR) CREATE TABLE short_tournaments (short_tournaments_id AUTO_INCREMENT PRIMARY KEY, Year VARCHAR, Position INT, Games played INT, Won INT, Tied INT, Lost INT, Goals Scored INT, Goals Against INT, Points INT, Postseason place VARCHAR) CREATE TABLE singles:_19_finals_8_titles_11_runner-ups (singles:_19_finals_8_titles_11_runner-ups_id AUTO_INCREMENT PRIMARY KEY, Outcome VARCHAR, Year INT, Championship VARCHAR, Surface VARCHAR, Opponent in the final VARCHAR, Score in the final VARCHAR) CREATE TABLE performance_comparison (performance_comparison_id AUTO_INCREMENT PRIMARY KEY, Cartridge VARCHAR, Bullet weight VARCHAR, Muzzle velocity VARCHAR, Muzzle energy VARCHAR, Source VARCHAR)  
SELECT Goals Against FROM short_tournaments WHERE Goals Scored = 30